Numerical Investigations of Reinforced Concrete Slabs Subjected to Contact Explosions

This study examines the behaviour of reinforced concrete (RC) slabs subjected to contact explosions through experimental investigations and numerical simulations. A contact explosive charge field experiment was conducted on a bi-directionally reinforced RC slab to characterise the resulting damage patterns. The experimental findings revealed localised perforation and substantial deformation of the reinforcement bars without bar rupture. A numerical model employing the RHT concrete and Johnson–Cook steel material models was implemented in Ansys Autodyn (v 2023 R2) to replicate the observed responses. Initial verification was carried out against data from the literature, and calibration was performed using the instantaneous geometric strain (IGS) as the erosion parameter. An optimal IGS value of 0.375 was found to reproduce the experimental damage most accurately. Subsequent parametric analyses of the validated models investigated the influence of slab thickness and reinforcement ratios on blast resistance. The results demonstrated that increasing the slab thickness substantially mitigates perforation, while higher reinforcement ratios improve overall structural integrity. This work confirms the reliability of the calibrated numerical models for predicting the response of RC slabs to contact explosions, and it offers valuable insight into the design of blast-resistant structures.